Film projection system

ABSTRACT

A film projection viewing system employs a projector to receive cartridges loaded into the projector in a manner completing a light path through the projector to a viewing screen. A film projector and cartridge having a substantially self-contained film transport therein cooperates to provide a system having a lens system with a focal length settable to a predetermined position in response to insertion of a cartridge into the projector.

This is a division, of application Ser. No. 517,919, filed Oct. 25, 1974now U.S. Pat. No. 3,951,536.

BACKGROUND OF THE INVENTION

This invention pertains to a film projection system using cartridges offilm to be loaded into a projector having a viewing screen for displayof images of the film from the cartridges therein. This inventionparticularly pertains to such a system in which the insertion of thecartridge into the system serves to establish a predetermined focallength in the lens system of the projector to provide repeatableaccurate automatic focusing among a number of such cartridges used witha single projector or when using one cartridge with a number of suchprojectors.

Heretofore, film projection viewing systems, such as microfilm readersystems, have employed projectors into which cartridges of film could bedisposed but, upon insertion of each cartridge into the projector,follow-on focusing of the projector can be expected to be required fromone cartridge to the next. In addition, it has been the rule that theprojector should contain the microfilm transport apparatus, such asmeans for tensioning the film as it arrives at a point for projection,as so to leave the cartridge in a relatively simple state ofconstruction involving the barest of elements therein.

It has been observed that there are substantial advantages to beobtained by providing the herein disclosed system as will be pointed outfurther below.

SUMMARY OF THE INVENTION AND OBJECTS

In general, a film projection system has been provided including aprojector having a relatively large hollow housing, an optical viewingscreen for receiving images projected onto the screen from a film, and alens system within the housing movable between advanced and retractedpositions along its own axis. A light source within the housing isdisposed and adapted to project light along a path defined through thefilm and the lens system so as to display an image onto the viewingscreen of the projector. Means carried by the housing and adapted toreceive a film cartridge loaded partially into the housing serves todispose film of the cartridge into the foregoing named light path. Thelens system is disposed so as to be moved in response to insertion ofthe cartridge thereby focusing the projection system. Finally, means areprovided for engaging the cartridge so as to limit the degree ofinsertion thereof to dispose the lens system at a predetermined positionproviding a predetermined focal length at which the film will beprojected accurately in focus. The cartridge includes an outer surfaceportion disposed and adapted to engage that portion of the cartridgelimiting the degree of insertion of the cartridge whereby engagement ofthe outer surface portion with a portion of the projector serves toestablish the appropriate predetermined focal length of the lens system.

It is a general object of the present invention to provide an improvedfilm projection system.

It is a further object of the invention to provide an improved filmprojection system characterized by means for establishing a repeatablepredetermined focal length within the projector in response to insertionof each cartridge therein to a predetermined degree.

It is another object of the present invention to provide a filmprojection system in which a portion of the projection light path from alight source to a viewing screen in the projector is defined through theenvelope of a cartridge insertion into the projector.

It is yet another object of the invention to provide an improved filmprojection system in which means are provided for laterally adjustingand guiding the film gate of a cartridge into alignment with the axis ofa lens system with the projector as the cartridge is inserted.

It is a further object of the invention to provide an improved cartridgefor use in conjunction with a projection system whereby the cartridgecan form a portion of the light path of the projection system and caninclude means for pretensioning the film within the cartridge to removedeformations in the film disposed at the film gate of the cartridge.

A further object of the invention is to provide an improved cartridge ofthe kind described in which a transducer is carried by the cartridge fordetecting index marks on the film within the cartridge.

An additional object of the present invention is to provide a filmprojection system in which the viewing screen can be disposed at one oranother of at least two stable states by changing the center of gravityof the projector and cartridge and other contents within the projector,preferably by sliding a weighted handle between advanced and retractedpositions so as to transfer the center of gravity of the apparatus fromone side to the other of a vertical plane extending upwardly andincluding a line of intersection defined between portions of the bottomof the apparatus.

The foregoing and other objects of the invention will be more readilyevident from the following detailed description of a preferredembodiment when considered in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagrammatic perspective exploded view of a cartridge andprojector system according to the invention;

FIG. 2 shows an elevation view taken along the line 2--2 of FIG. 1;

FIG. 3 shows a side elevation centerline section view of the projectionsystem of FIG. 1 (but with the cartridge unit thereof inserted into theprojector unit);

FIG. 4 shows a transverse section view taken along the line 4--4 of FIG.3;

FIG. 5 shows a side elevation section view of a receiver unit and lenssystem of the projector unit with the cartridge shown in full line beinginserted into the receiver;

FIG. 6 shows a view similar to FIG. 5 with the cartridge fully insertedinto the receiver unit with portions of the cartridge broken away forclarity;

FIG. 7 shows a diagrammatic perspective view of a cartridge for use inthe system according to the invention with portions broken away forclarity;

FIG. 8 shows a side elevation section view of FIG. 7 taken along theline 8--8 thereof;

FIG. 9 shows a plan view in section of the take-up reel shown in thecartridge of FIG. 7 and taken along the line 9--9 of FIG. 10;

FIG. 10 shows a side elevation section view taken along the line 10--10of FIG. 9;

FIG. 11 shows a side elevation section view in reduced detail takenalong a diameter of the supply roll shown in FIG. 7; and

FIG. 12 shows a diagrammatic perspective view of a cartridge inverted soas to disclose the underside thereof.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

A film projection viewing system 10 includes a projector unit 11including a relatively large hollow housing 12. An optical displayviewing screen 13 is disposed at the front of unit 11 for receivingimages projected onto the screen from the backside. Accordingly, screen13 is preferably of a translucent semi-rigid material, such as groundglass or suitable plastic material accomplishing the same or similarfunction.

Thus, by projecting an image onto the backside of screen 13, the imagecan be viewed from the front side thereof by the operator of the system.

A lens system 14 disposed within housing 12 includes a pair of lenses16, 17 disposed in fixed spaced relation to each other by suitable meanswithin a sleeve 18 disposed within a generally clindrical holder 19. Aninwardly extending flange or lip 21 is formed to retain sleeve 18 frommoving longitudinally outwardly of holder 19 to the right (as shown inFIGS. 5 and 6) while a snap ring 22 retains sleeve 13 within holder 19from moving longitudinally to the left (as shown in FIGS. 5 and 6).

A radially outwardly extending flange 23 formed about the outer end ofholder 19 serves to engage a spring 24 disposed within a bracket 26whereby the lens system is arranged to be moved between advanced andretracted position against the urging of spring 24.

During such movements of the lens system, bracket 26 engages and guidesthe outer edge of flange 23 while the trailing portion of holder 19rides upon the annular surfaces 27, 28. A stationary lens 29 directslight upwardly through the light passage 31 from a projection bulb 32whereby whenever cartridge 33 has been properly loaded into receiver 36light from bulb 32 will be transmitted against mirror 42 and outwardlyvia lens system 14 to screen 13.

In general, a film transport cartridge 33 containing a length of filmwrapped to form supply and take-up rolls as will be described furtherbelow and further including a film transport mechanism for transportingthe film from one roll to the other in opposite directions is arrangedand designed to conform to the special configuration of receiver opening34.

Thus, that portion of projector unit 11 formed and adapted to receivecartridge 33 therein shall be referred to hereinafter as the receiver 36of projector unit 11.

Receiver 36 serves to receive cartridge 33 within opening 34 whereby ascartridge 33 is inserted into receiver 36, the leading end 33a ofcartridge 33 serves to engage the inner end (FIGS. 5 and 6) of holder 19and, upon further insertion into receiver 36, cartridge 33 will movelens system 14 axially to compress spring 24.

Means are provided for limiting the degree to which cartridge 33 can beinserted into receiver 36 whereby lens system 14 will be properly infocus with respect to film 41 within cartridge 33.

Cartridge 33 includes window openings 37, 38 and a mirror 42 disposedand arranged whereby, upon inserting cartridge 33 into receiver 36 toits limited extent, windows 37, 38 and mirror 41 will all line up withthe light path 39 originating from projector bulb 32 thereby projectingan image of the film 41 disposed in light path 39 onto the back surfaceof screen 13 through the folded light path construction now to bedescribed.

Accordingly, referring to FIG. 3, light projected from lens system 14first strikes a mirror 43 mounted on the inner surface of rear panel 44of housing 12. The angle of light path 39 and the angle of mirror 43 aredisposed whereby the front panel forming viewing screen 13 will receivethe light projected therefrom.

Means for holding cartridge 33 in its fully inserted position comprisesa readily releasable latch element 46 mounted upon the end of a leafspring 47 which is, in turn, fixed by the rivet 48 to the interior upperside wall of receiver 36. The upper surface of top wall 49 includes adetent 51 disposed to engage the lower edge 46a of latch element 46 ascartridge 33 advances into receiver 36.

At the time latch element 46 engages detent 51, lens system 14 will bepositioned to be closely in focus and, as noted above, windows 37, 38will be disposed in light path 39 for passing light from projector bulb32.

Further advance of cartridge 33 into receiver 36 is prevented by thelimiting means comprised of the laterally extending portions 52 of theT-shaped body 53 on the under surface of cartridge 33. Portions 52 aredisposed for engagement with arresting contact regions 54 defined on thefront surface of projector unit 11 flanking the rectangularly shapedgroove 56 adapted to accommodate entry of the rectangularly shaped stemportion 57 of the T configured body 53 beneath cartridge 33.

From the foregoing, it will be readily evident that cartridge 33 can beinserted into opening 34 of receiver 36 in only one possible manner,namely, right side up and with the film gate end 33a of cartridge 33leading into receiver 36.

The foregoing arrangement makes it impossible to misload cartridge 33into receiver 36. The lateral limiting portions 52 of body 53 engage thearresting regions 54 defined adjacent receiver 36 on the face of housing12, whereby cartridge 33 cannot be forced too far into receiver 36.

Accordingly, the provision of the guide groove 56 extending into thecartridge receiving opening 34 guides the entry of body portion 57carried on and protruding from the under side of cartridge 33 to insurethat cartridge 33 will be inserted right side up. In addition, however,further body means such as the cross bar portion of the T-shaped body 53provides lateral limiting portions 52 protruding away from cartridge 33for engaging the arresting contact regions 54 so as to limit the degreeof insertion of cartridge 33 and thereby establish the correctdisplacement of lens system 14 so as to place the system in precisefocus.

Cartridge 33 includes a gate opening 58 disposed and adapted to bepositioned centrally on the axis 59 (FIG. 5) of lens system 14.Accordingly, a pair of converging guide surfaces 61 formed withinopening 34 at the interior sides thereof serve to engage convergent sidewall portions 62 of cartridge 33 disposed at the leading end thereof soas to laterally position cartridge 33 with respect to the axis 59 oflens system 14.

Means, as now to be described, have been provided for disposing viewingscreen 13 of projector unit 11 at one or the other of two stablepositions, either as shown in full or phantom lines in FIG. 3, thephantom line position being designated by the reference numeral 13'.Accordingly, housing 12 comprises a large, hollow body having a toppanel 63, a front panel or viewing screen 13, a back panel 44,confronting side panels 64, 66, and a bottom panel 67 having first andsecond portions 67a, 67b respectively laid in two different planes. Theplane of panel 67a merges with the plane of panel 67b at a relativelysmall angle 68 so as to define a line of intersection 69 therebetweenforming a fulcrum 71.

Means are carried by housing 12 for readily relocating the center ofgravity of projector unit 11 so as to cause projector unit 11 to rest ina first or second stable condition on one or the other of the two bottompanel portions 67a, 67b. This permits the viewing screen 13 to bedisposed at one or another of two selected angles.

Accordingly, a carrying handle 72 is arranged to slide along the toppanel 63 and is fastened thereto by means of a tongue-and-groovecoupling. For example, handle 72 includes tongue portions 72a disposedto engage beneath the overhanging longitudinally extending lips 73formed in top panel 63.

As thus arranged, handle 72 can be readily moved longitudinally of theslot 74. Handle 72 is formed of a hollow rigid or semi-rigid materialsuch as plastic and contains high density, relatively heavy materialtherein, such as BB's or bird shot 76, or other suitably heavy materialwhereby the carrying handle is of sufficient weight and has asufficiently movable displacement to be able to transfer or displace thecenter of gravity of housing unit 12 and the contents thereof, (such asthe electronic package 75 and cartridge 33 disposed within receiver 36),from one side of a vertical plane extending upwardly through the line ofintersection 69.

As now to be described, cartridge 33 includes a film transport apparatuswhereby means are provided within envelope 77 or case for pre-tensioningfilm 41 at gate opening 58 so as to lie taut and free of deformations inthe surface of the film thereat. By providing this tensioning of thefilm, deformations in the film at gate 58 are removed so as to avoidcreating aberrations in the projected image from the film.

Transducer means in the form of the light responsive transducer element78 is carried by envelope 77 and disposed and adapted to register with aportion of film 41 moving within the envelope. Transducer 78 serves todetect indicia of known type and style carried by film 41 foridentifying frames of film 41.

In addition, means forming electric leads 81 are coupled to transducer79 and carried by envelope 77 in position for coupling transducer 79into and out of a circuit having portions carried within receiver 36.The circuit is schematically represented by and includes the interiorcontacts 83 disposed upon the interior side walls of opening 34 ofreceiver 36 for engaging contacts 82 located on both sides of cartridge33 and coupled to leads 81.

Thus, as cartridge 33 is urged forwardly into operative position withinopening 34, contacts 82 will engage contacts 83 which, in turn, form theconnection points to known circuitry involving counters and the like fordetermining the number of index marks counted by transducer 78.

A drive motor 84 arranged with a drive spindle 86 carried on thearmature of motor 84 engages a drive wheel 87 of cartridge 33 fortransporting film from one roll thereof to the other, all as to bedescribed further below. However, for now, it is pertinent to note thatthe drive mechanism is contained within housing unit 12 while the filmtransport apparatus and film tensioning means has been advantageouslycontained within cartridge 33. Further, when detent 51 has engaged catch46, spring 24 will be substantially compressed whereby upon release ofcatch 46, spring 24 will boost cartridge 33 partially out of receiver 36where it can be readily removed. Knobs 85, 90 schematically representmotor controls of known style for selectively varying the rate anddirection of rotation of the armature of motor 84 for correspondinglydriving film 41 via wheel 87.

A film transport arrangement as disclosed in FIGS. 7, 8, 9, 10 and 11 isconstructed as now to be described.

Cartridge assembly 33 includes a generally hollow envelope 77 comprisedof a pair of opposed half sections 121, 122. Section 121 forms the topand includes a transverse top panel 49, while section 122 generallyforms the bottom and includes a bottom panel 60.

The bottom of envelope 77 further includes an elongate downwardlydepending T-shaped rectilinear body 53 forming a key portion adapted toengage the keyway groove 56 so as to insure proper orientation ofcartridge assembly 33 as it is inserted into projector unit 11.

As thus arranged, bottom panel 60 of envelope 77 provides a base memberfrom which rolls of film can be supported for rotation. A mountingspindle 129 extends into both the top and bottom panels 49, 60 tosupport hub 131.

Hub 131 includes a journal portion 131a with a bearing sleeve 135located between spindle 129 and portion 131a to permit rotation of hub131.

The ends of bearing sleeve 135 are spaced by shims 40 to form theconfronting surfaces of panels 49, 60.

Hub 131 further includes a peripheral portion 131b of generallycylindrical construction adapted to receive film 41 wrapped thereaboutto form the supply roll 132.

The term "supply roll" in the present instance is used simply as aconvention for conveniently explaining the function and operation of theapparatus since it will be readily evident that by merely reversingmotor 84, the transport becomes bi-directional and can feed film in bothdirections whereby roll 132 could also be considered a "take-up" roll.

A base or drive body portion 131c of hub 131 extends radially outwardlybeyond the convolutions of film 41 wrapped about flange 131b so as tolie beneath film 41 as it is wrapped about hub 131. Thus, means forrotating hub 131 includes a peripheral groove 134 formed into the sideedge of drive body 131c.

As will be evident further below, an endless, cyclically moving drivebelt 136 lies in groove 134 for rotating hub 131 about the rotationablemounting means defined by spindle 129 and its associated bearing.

A "take-up" roll (used only in the sense that the other roll wasreferred to as a "supply" roll using the arbitrary convention noted) ismounted for rotation about spindle 133. Spindle 133 extends into and issecured in both the top and bottom plates 49, 60. The take-up rollassembly 137 includes a rotating disc-like drive body 138 also formedwith a peripheral groove to receive drive belt 136.

Body 138 includes a sleeve bearing 145 spaced by shims 150 from plate 60to permit rotation of body 138 about the axis of spindle 133.

A hat-shaped take-up hub element 139 includes film 41 wrappedtherearound and a peripheral outer brim portion 141 therebeneath, aswell as a downwardly depending journal portion 142 disposed for rotationabout a sleeve bearing 143.

Thus, drive body 138 and hub 139 rotate about the same axis of rotationindependently of each other (except for the spring 148 couplingtherebetween). Finally, body 138 includes an axially extendingcylindrical portion 146 extending upwardly within hub element 139 andhereafter referred to as the coupling portion of drive body 138.

Accordingly, there has been provided a rotatable drive body and atake-up hub element 139 disposed for independent rotation to wrap film41 therearound. Another drive body also supports the supply roll forrotation to feed film therefrom to the take-up hub element 139.

Finally, coupling means in the form of portion 146 and the rivets 147 orother suitable attaching device couple one end of spring 146 thereto formovement with the upwardly extending cylindrical rim portion 146 forrotation therewith relative to hub element 139.

Clock spring 148 interconnects between hub element 139 and the couplingportion 146.

In operation, clock spring 148 can be pre-tensioned to tend to rotatetake-up hub element 139 in a direction tending to wrap film 41therearound. Finally, drive means in the form of motor 84 and itsassociated drive spindle 86 engage the drive gear or wheel 87 forrotating drive pulley 149 to move belt 136. Belt 136 rotates the take-uphub drive body 138 and the outer end of resilient clock spring 148 towind film 41 about hub element 139 while rotating the supply roll (viathe film) for unwinding film therefrom.

It will be readily evident that the path of movement of film 41 proceedsfrom hub 131 to flanged guide roller 125, past transducer 78, acrossanother flanged idler 130, and then to take-up roll assembly 137.

In operation, the presence of the pre-tensioned clock spring 148 servesto tend to rotate hub element 139 in a wind-up direction whereby thewinding tendency of spring 148 serves to maintain tension in that spanof film 41 defined between the supply and take-up rolls.

In feeding film from supply roll 132 to take-up hub element 139, spring148 constitutes a portion of the drive coupling whereby rotation of body138 rotates the cylindrical portion 146 which, in turn, rotates rivets147 at one end of spring 148. At the other end of spring 148 journal hub142 is attached to spring 148 so as to rotate the hat-shaped outer hubelement 139 in response to the spring rotation.

By pre-tensioning spring 148, a resilient means is provided in the drivetrain tending to add to the angular rate of rotation of hub element 139when hub element 139 is receiving film and to subtract from the angularrate of rotation of hub element 139 when film 41 is being unwound or fedin the opposite direction from hub element 139 so as to maintain tensionin that span of film extending between the two hubs as the film is beingfed in either direction.

It has been observed that the restraint imposed by coupling both thesupply and take-up rolls together by means of belt 136 and the restraintafforded by drive motor 84 coupled to drive wheel 87 all combine toprevent the pre-tensioned spring 148 from driving the film under its ownpower. However, it is to be appreciated that only minimal energy needsto be drawn from motor 84 to drive the supply and take-up rolls.

Thus, the drive means provides sufficient restraint via coupling one endof spring 148 to the drive means to prevent the coupled end of spring148 from freely unwinding so as to release the energy of the spring.

Further, it should be readily evident that the number of pre-tensionedturns required to be made to spring 148 will be minimal since both rollsare coupled to rotate together and only the difference in turns betweenthe supply and take-up rolls is required to be compensated for by theenergy in the spring.

From the foregoing, it will be readily evident that there has beenprovided an improved film projection system suitable for use withmicrofilm or other film, and in which a repeatable focal length isestablished in response to insertion of a film cartridge into a receivercarried by the projector unit. Thus, repeatable focal length performanceis accomplished even though the projector must employ many cartridgesand, accordingly, no re-focusing is necessary.

Further, from the forgoing, it is evident that the plane of the film atthe film gate will lie under tension in order to eliminate deformationsin the surface of the film which otherwise might cause aberrations inthe projection of the images recorded on the film.

I claim:
 1. A film projection viewing system comprising a projectorincluding a relatively large hollow housing, an optical display viewingscreen for receiving images projected onto said screen from a film, alens system disposed within said housing, a light source disposed withinsaid housing and adapted to be projected along a light path definedthrough a film and said lens system to project an image onto saidviewing screen, means carried by said housing for receiving a filmcartridge, a film cartridge within the last named means, a filmtransport within the cartridge including first and second rolls of filmrespectively wrapped about first and second hubs, a window formedthrough said cartridge and aligned in the path of said film, a drivebody coupled for rotation with the first hub and disposed coaxially ofand substantially coplanar with the second hub, a coil spring having oneend connected to the drive body and the other end connected to thesecond hub to provide a resilient driving connection between the drivebody and the second hub, said spring being pretensioned to tension thefilm extending between the rolls to cause that portion of said filmdisposed across said window to lie in a plane free of deformation in thesurface of said film portion as said film moves in either of twodirections, and motive means carried in said housing independently ofsaid cartridge and disposed to engage and drive said transport throughsaid drive hub in either of two directions at varying rates while saidfilm remains under the tension applied by said spring.
 2. A filmtransport cartridge for use with a projector of a type having means forreceiving and holding the cartridge, said cartridge comprising ahousing, means forming a light path passing into and out of saidhousing, a length of film wrapped about first and second hubs withinsaid housing for movement across said light path to position said filmfor projection of an image of information carried by said film, a drivebody coupled for rotation with the first hub and disposed coaxially ofand substantially coplanar with the second hub, and a coil springconnected to the drive body and second hub to provide a resilientdriving connection between the same, said spring being pretensioned totension the film between the first and second hubs and thereby maintainthe film substantially flat and free of deformation in the region ofsaid light path.
 3. A film transport cartridge according to claim 2wherein the means forming a light path includes a window in one wall ofsaid housing and a film gate opening aligned therewith.
 4. A filmcartridge assembly of a type adapted to contain a length of film wrappedto form supply and take-up rolls comprising an envelope adapted to beinserted into a receiver portion of a projector, a film gate carried bysaid envelope, a film transport means within said envelope for feedingfilm from one roll to the other in a manner positioning the film forprojection of images thereof via said gate, means defining a light pathinto and out of said envelope via said film and said gate to permitlight to be projected through the envelope and film, first and secondhubs about which the film is wrapped, a drive body coupled for rotationwith the first hub, and a spring member interconnecting the drive bodyand the second hub to provide a resilient drive connection between thesame, said spring member being pretensioned to maintain sufficienttension in that portion of film disposed at said gate to hold saidportion of film in a substantially flattened condition.
 5. A cartridgeaccording to claim 4 comprising transducer means carried by saidenvelope and disposed and adapted to register with a portion of the filmtherein, said transducer means serving to detect indicia carried by saidfilm for identifying frames of said film.
 6. A film cartridge accordingto claim 5 comprising means forming electric leads coupled to saidtransducer means and carried by said envelope in position for engagementwith contacts carried by the receiver portion of the projector housingwhen the cartridge is inserted therein.